Machine for bending sheet metal shapes



July 14, 1931. A. RAFTER 1,813,951

MACHINE FOR BENDING SHEET METAL SHAPES Filed Dec. 8, 1928 3 Sheets-Sheet 1 ATTORNEY July 14,- 1931; 7A. RAFTER 1,813,951

MACHINE FOR BENDING SHEET METAL SHAPES Filed Dec. 8, 1928 5 Sheets-Sheet 2 INVENTOR ATTORNEY Patented Jul 14, 1931 UNITED STATES PATENT OFFICE ALBERT RAFTER, OF BELLEVILLE, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 SAID-ALBERT RAFTER AND JOHN C. RAFTER, JR", BOTH OF IBELLEVILLE', NEW

JERSEY MACHINE FOR IBENDING SHEET METAL SHAPES Application filed December 8 1928.. Serial Iva- 324,706.

- structure has-been found objectionable in that, the solid metal bed and the solid metal hammer often crack when subjected tothe tremendous stresses common in the stamping operation; also themetal slde pleces, when sub ected to' contmue'd reversal of stresses,

1 become brittle and crack. In View of the tremendous size of these machines and their problem inasmuch as such parts of the machine may notbe readily replaced.

It is therefore, an object of this invention to (provide a bending machine in which the be and the hammerare so deslgned as to eliminate the danger'of cracking when subjected to the tremendous stresses incidental to a stamping operation.

These, and other objects are attained by the novel construction, combination andarrangement of arts hereinafter described and shown in t e accompanying drawings, constituting a, material part of this disclosure and in which: I 1 g Figure 1 is a rear view of the stamping press.

Figure 2 is an end view of the machine.

re 1. igure 4 is a view taken on line 4-4 ofF gure 1.

Figure 5 is a view taken on line 5+5 of Figure 4.

eferring to the drawings, the machine is shown to have a bed 6 of cast steel, which F Figure 3 is a view taken on line 33 of 1 9. Fixed to the guide 9 is a bracket 10, whleh supports an electric motor 111, the

latter driving, through a belt 12, the main drive shaft 13; A bracket 14 fixed to one end of the bed is provided with a bearing 15 in which is journalled one end of the drive shaft 13, the remainder of theshaft being journalled in a bearing 16 on the guide 9, and in a bearing 17 carried by a bracket 18 fixed to the rear of, the bed.

A gear 19 fixed to the shaft 13 adjacent the bearing 17 mesheswith a larger gear 20 fixed to a shaft 21 journalled in bearings 22, 23 and 24 respectivelycarried by the. bracket 18 and the guides 8 and 9. Fixed,

to ends of shaft 21 are gears 25 and 26 which drive the large gears27 and '28, re-

spectively.

The gear 28 is fixed to a short shaft 29, to

which is fixed .an eccentric 30 having a bead 31 which lies in a groove in'a twopart bronze bearing 32 which lies within a collar comprising two parts 33 and 34, which are bolted together; The lower part 34 is integral with a connecting rod 35 which has an aperture 36 to receive'bolts by which straps 35an1ay be connected to' the connecting rod 35 and the sides of a yoke 37, the latter being also provided with bolt holes 38 and 39. v

The lower end of connecting rod '35 is arcuate in shape andrests in an arcuate groove in a cushion block 40 positioned in the lower'part of yoke 37. The bed will be seen to have a. plurality'of longitudinal and transverse webs 41 and '42 which are cutaway at 43 as shown in Figure l to accommodate the eccentric collar. The sides of the bed are flanged at 44 and have bolted thereto the flanges 45 of bearings 46 and 47 for the shaft 29. Sincethe space between the eccentric collar and the end of the bed is greater than the length of bearing 47 between the -sides of yoke 37 is greater than upper 'end of the Illlt 52 is keyed to a worm wheel 55 to rotate therewith, and the worm wheel engages a worm 56 which may be I manipulated by a hand wheel 59. With this structure, theheight of the hammer may be adjusted by rotating the worm 56 which in turn rotates the worm wheel 55 and collar 52, the latter being restrained from longitudinal movement and due to its threaded engagement with bolt 51 causesthe latter to move longitudinally upward or downward as may be desired to adjust the height of the hammer.

As will be seen from Figure 4, the hammer comprises substantially an I-beam with its central web projecting at 57 to support a die which cooperates with a female die positioned in a groove 58 in the bed, (not shown).

It will be noted that the yoke structure 37, as well as the eccentric shaft arrangement above described is the same at each end of the machine; also the threaded bolt and nut means for adjusting the height of the hammer are the same at each end of the hammer.

In operation, power is derived from the electric motor 11 to rotate the large gear ters Patent, is:

wheels 27 and 28 which in turn rotate the stud shafts 29 at each end of the machine to rotate the eccentrics fixed to said shafts, which in turn cause the yokes to alternately rise and fall, carrying the hammer with it to perform the stamping operation.

From the above description it will be seen that there has been provided a machine which enables the bending of pieces of sheet metal of greater length than the machine, as such pieces of sheet metal may be introduced to the machine from the ends by passing between the sides of the yoke 37. This has heretofore been impossible with other stampifig machines, since the end pieces of such machines have been solid and provided with no apertures through which thematerial to be stamped could be passed.

It will also be noted that the manner in which the hammer is mounted on the 1 yoke and thestructure of the yoke itself accommodate themselves to various large stresses without damage, than is the case when the hammer and bed plate are solid.

The arrangementof the bed and yokes enables the driving mechanism to be carried entirely on the bed, thus eliminating obstructions in the path of the hammer so that the latter may be designed to have maximum strength for a given weight. By mounting the driving mechanism on the bed, the machine is complete for operation under all circumstances and may be efliciently op-v erated upon uneven foundations.

In machine's havin solid side pieces, the force of the blows of the hammer causes a twisting and reversal of stresses in. the side pieces with the result that the latter frequently crack. But with the yoke structure described herein the blow of the hammer is taken largely by the bed and the block 40 with the result that there is practically no twisting or reversal of stresses in the yokes 37;

In order to prevent the likelihood of twisting in the guides 8, 9 and 49, the u per .ends of said guides are connected by ars 62. j

The foregoing disclosure is to be regarded as descriptive and illustrative only, and not as restrictive or limitative of the invention, of which obviously an embodiment may be constructed including many modifications without departing from the general scope herein indicated and denoted in theappended claim. I

Having thus describe any invention, what I claim as new and Idesi e to secure by Let- In a bending'machine, a bed, rear and front guides fixed to the bed, yokes at the ends of the bed, a hammer mounted on the yokes, said hammer being slidable in the guides, shafts mounted at each end of the bed, eccentric members fixed to said shafts, said eccentric members being connected to the okes to reciprocate the latter when the sha ts are rotated, and means supported bythe rear guides to rotate the shafts.

Thisspecification signed this sixth day of December, 1928. 1

' ALBERT RAFTER. 

